How Do Solar Panels Work (simplified)

The Sun's Potential

Almost all energy on this planet comes from the Sun. Oil and gas
come from living things that died a very long time ago and those living
things all got their energy from the Sun. Even wind currents and the
water cycle rely on the Sun to some degree. The Sun puts out more
energy that reaches earth than we could ever use. So why is there an
energy shortage?

Well theoretically you could power an electric car with a solar
panel that charged a battery that powered the engine. In reality
however this would be difficult with our current solar cell technology,
but there has been research that has indicated that it might be
possible in the future. In the laboratory solar cells have shown promise but getting the same results in the real world at a price the average person could afford is still a ways off.

So what is a Solar Cell?: The first thing you need to under stand is
why electric current "flows". To simplify this lets take a car battery
and you probably know that there is a positive and a negative terminal
usually marked by a large + or -. The simple explanation for how the
battery works is that at the negative terminal there is a large number
of electrons and at the positive end there is big shortage of
electrons. In nature things like to balance out, so if you connect
these terminals with the car's electrical circuits between them, the
electrons will flow from the negative to the positive until there is a
balance of electrons, at which point we say the battery is dead. We
then use a battery charger to force things out of balance again, so that
once again we have "all the electrons back to one side" so that there
is a natural tendency for the electrons to flow again. This difference
between the + and the - is called difference in potential, and we call
this voltage. A fully charged car battery has 12 volts of difference in
potential. So in order to get a flow of electricity we need to have
some area that has more electrons than another and connect the two
areas.

Some Solar Panels

Here is a neat solar panel from a company in Vermont, notice that it can be adjusted to the Sun

Here is a basic 5 to 10 watt solar panel that can be used to charge a battery or run a small appliance.

This is a somewhat dramatic presentation of a solar panel that powers a light fixture in a garage or closet.

So How Do Solar Cells Work?

You have probably heard of an "electric eye", This is based on a
principal called the photo electric effect. An over simplification of
this is that some materials will give off electrons when exposed to the energy of
certain light.

Well the solar cell takes this a step further and uses
something called the photo voltic effect. Now again an over
simplification is if you get a material to give off electrons using the
photo electric effect and those electrons are collected by another
nearby material, the nearby material would have excess electrons and
the material that gave off the electrons would have a lack of
electrons. This is just like the battery from earlier. In this way a
solar cell becomes like a battery and can generate an electrical flow.
If you put a bunch of these cells together you get a solar panel.

Now the problem with this is a term called efficiency, which is
basically what do you get out compared with what you put in. In nature
you always get less out than what you put in because there is always
heat loss, friction, etc... Solar cells are very inefficient. The
first solar cell was built by a guy by the name of Charles Fritts in
1883 and it's efficiency was about 1%. This means that you would have
to put in 100 units of energy to get one unit of energy produced. The
sun's energy is free and that is the only reason anyone ever wasted any
time on such a bad return.

Today you can buy solar panels that have
efficiency ratings from 3or4% to the mid 20% depending on the type of
solar cell used and how they are put together. The greater the
efficiency the higher the price. In the labratory efficiency ratings
of over 40% have been reported but in general use affordable panels
generally run between 8 and 20% and of course some are even less
efficient and are very inexpensive and are used as science projects,
toys and novilties.

So the days of powering your car with a solar panel is not fully
here yet, but it might not be that far away since advances are being
made daily in this field. Of course the prototypes might only be
affordable to Bill Gates, but the first "cell phones" were the size of a
large brick and could only be purchased by the rich and look at those
today. Space vehicles are solar powered and perhaps soon yours will be
also.

For more information go to:

Solar Energy AdvantagesThis site provides news and information regarding solar energy and new solar innovations. Solar Energy is not without barriers but the advantages far out weigh the disadvantages.

Comments

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Marc Rance 4 years ago

[quote]8192 characters left.[/quote]

Wonderful info, Thanks..

Incredible plenty of excellent facts!

Author

GreenMathDr 6 years ago

Thanks, as a math and science guy I could get real technical. But if some wanted a real technical explanation they could get it in a text book.

mini projects for cse 6 years ago

Brilliant hub, really nice explanation, very informative too.

joyce.blue 7 years ago

Excellent Hub! this is very informative and really tell how solar panels work. Although I am quite familiar with solar panels but this hub really explained all the things I have in mind.

Author

GreenMathDr 7 years ago

Joe, usually a solar panel is used to charge a battery which then powers the item. Sometimes the panel is attached directly to the thing it is powering but obviously this would only work during daylight hours and would not be practical for most uses. Jokes about solar powered lights that only work in the daytime are based on using a solar panel to run lights without a battery.

I'm not sure I fully understand the computer keyboard scenario but if not recharged all batteries will die eventually. In normal application the panel would recharge the battery during the daylight hours. but if you mean die completely as in no longer rechargeable then eventually that too will happen unless someone invents a battery that lasts "forever". (That might make a good Sci-Fi movie. Civilization is long gone but the energizer bunny and all battery powered items are still going.)

Joe 7 years ago

I'm very unfamilar with the workings of solar power.

I just wrote a blog about Logitech's new solar powered keyboards,

but my friend brought up a good point (i think)

Even if something is powered by solar panels, there's still some sort

of "battery" that is getting charged... correct?

So if someone made a computer keyboard using solar panels,

eventually the battery (which is powered by the solar power)

would die... correct?

Good post by the way

Author

GreenMathDr 8 years ago

You know there was just a break through in Germany that will really cut the price of Solar panels if it works I'll get the data to you as soon as I find it.

Simon Cook 8 years agofrom NJ, USA

I've been thinking of investing in this for my house for a while - maybe in a couple of years! Great HUb!